The invention relates to a charging device for an electric vehicle.
Various charging technologies using cables are known for the charging of an electrical energy storage device of an electrically driven motor vehicle. First, there is the technology of charging using alternating current (AC), wherein there is a corresponding charging device in the vehicle which has an AC/DC converter. In addition, direct current (DC) charging is known, wherein the charging device is situated in an external charging station outside of the vehicle, and direct current is fed via an electric cable from the charging station to the energy storage device in the vehicle. In most cases, the charging capacity is greater in DC charging than in AC charging.
The vehicle can be connected to the charging station for AC and/or DC charging via various types of plug systems. For DC charging, the charging connector on the vehicle is configured with corresponding contact elements which are galvanically connected to the electrical energy storage device being charged in the vehicle. In this case, assurances must be made that if a person touches the contact elements with a finger, when the charging connector is unoccupied, current does not flow through the person. This is achieved conventionally by opening switch devices, such as contactors, for example, in the electrical connection lines between the contact elements and the electrical energy storage device.
The problem addressed by the invention is that of creating a simple charging device for an electric vehicle which ensures protection against the touching of DC contact elements.
This problem is addressed by the charging device according to embodiments of the invention, which is intended for an electric vehicle, that is, it is a charging device positioned on-board the vehicle. The term “of the electric vehicle” should be understood broadly, and can include any type of motor vehicle which can be driven electrically, and wherein the energy storage device thereof can be charged electrically. This can be a vehicle driven only by electricity, and optionally also a hybrid vehicle which has an internal combustion engine in addition to an electric drive.
The charging device serves the purpose of charging an electrical energy storage device configured for the drive of the electric vehicle. The term “electrical energy storage device” in this case should be understood broadly, and can particularly include a plurality of electrical energy storage devices and/or storage elements. In one preferred variant, the electrical energy storage device is a high-voltage battery.
The charging device includes a first charging connector on-board the vehicle, that is, the charging connector is made for installation in the electric vehicle. The first charging connector serves the purpose of making a mechanical connection to a second charging connector of an external charging station which does not belong to the vehicle. The second charging connector and/or the charging station in this case are not part of the charging device according to the invention. The first charging connector of the charging device has two contact elements for the purpose of charging the electrical energy storage device in the electric vehicle using direct current. These contact elements are capable of producing an electrical connection to the charging station, via the contacting of two contacts of the second charging connector, when the first and the second charging connectors are connected mechanically. The charging device also includes a galvanic connection from the contact elements to the electrical energy storage device, wherein—if the charging uses direct current—direct current flows into the electrical energy storage device, to charge the same, via the galvanic connection. The direct current is fed to the contact elements of the first charging connector via the contact elements of the second charging connector. The charging device also includes a control device for the purpose of monitoring the charging process of the electrical energy storage device, wherein the control device is able to communicate with the charging station.
The charging device is characterized in that at least one of the two contact elements of the first charging connector is able to move between a first and a second position. In this case, the at least one contact element in the first position is withdrawn into the first charging connector, and particularly retracted. The term “withdrawn” in this case should be understood to mean that the corresponding contact element is not accessible to the touch of a user from outside of the vehicle when the first charging connector is unoccupied. Accordingly, the at least one contact element is arranged in the second position in such a manner that it contacts the corresponding contact of the second charging connector when the first and the second charging connectors are connected mechanically. The control device in this case controls the movement of the at least one contact element in such a manner that this contact element is moved into the second position only upon a mechanical connection between the first and the second charging connector, and otherwise is in the first position.
An efficient protection against touch is achieved by means of the charging device according to the invention by a mechanically movable contact element. In the configuration, the forces resulting from the insertion of the plug when the first charging connector, on-board the vehicle, is brought together with the second charging connector, of the charging station, are reduced because the contact between the corresponding contact elements and contacts, which involves friction, occurs after the mechanical connection of the charging connectors.
In one particularly preferred embodiment of the charging device according to the invention, the galvanic connection to the electrical energy storage device cannot be interrupted—that is, there are no switches, and specifically no contactors, to interrupt this connection. In this way, it is possible to reduce the costs of the charging device because it is possible to dispense with corresponding switches and/or contactors. Nonetheless, the configuration still ensures protection against touch as a result of the fact that the contact elements remain in the withdrawn position when the charging connector is unoccupied.
In a further preferred embodiment of the charging device according to the invention, the two contact elements used for direct current charging are contact pins which preferably contact, as contacts, corresponding contact sleeves in the second charging connector.
In a further, particularly preferred embodiment, the charging device can also carry out an alternating current charging process if required. In this case, the charging device also has further contact elements for the purpose of charging using alternating current. These contact elements are connected to an AC/DC converter which is included for the purpose of converting the supplied alternating current into direct current for the purpose of charging the electrical energy storage device.
Depending on the embodiment, the first charging connector of the charging device can have different designs. In a particularly preferred embodiment, the first charging connector is based on the IEC 62196-3 standard, which describes plug connectors for simultaneous direct current and alternating current charging. The charging connector is preferably of the COMBO1 or COMBO2 type or the DC-Type 2 of the IEC 62196-3 standard. Nonetheless, the first charging connector can also have a different design. In addition, contact elements which are used both for direct current and for alternating current charging can also be designed as movable contact elements according to the invention.
In one particular embodiment, both contact elements, used for the purpose of direct current charging, are configured as contact elements with protection against touch, and can move from the first into the second position. In this way, the protection against touch is further improved.
In a further embodiment, the charging device has a locking device to lock the second charging connector in the first charging connector upon a mechanical connection between the first and the second charging connector. Such locking devices are known in the prior art. The locking in this case is preferably implemented by the control device of the charging device when a mechanical connection between the first and second charging connector is detected.
In a further embodiment of the charging device according to the invention, upon the mechanical connection between the first and the second charging connector, a communication connection is established between the control device and the external charging station, and particularly a corresponding control device of the external charging station. The communication connection is particularly made via an electric contact. In one preferred embodiment, the known pilot connection is used for the communication.
In one particularly preferred variant, a charging communication is carried out via the communication connection described above, for the purpose of setting parameters in the charging device by way of the control device. When the control device allows the direct current charging as part of the charging communication, the at least one contact element is moved from the first into the second position. This means that the electric contact for the direct current charging process is only established once the direct current charging actually starts, thereby increasing the safety.
In a further embodiment, the at least one contact element is moved via an actuator which is driven electrically. The at least one contact element in this case is preferably held in the first position via a return force, and moved from the first into the second position via the actuator, against the return force. In this way, even if the actuator fails, the configuration ensures that the contact element is in the withdrawn position.
In addition to the charging device described above, the invention also relates to an electric vehicle which has an electrical energy storage device to drive the same, wherein the electric vehicle includes the charging device described above and/or one or more preferred variants of the charging device described above.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.